This invention relates to apparatus for writing and for producing signals representative of the writing, and, more particularly, to a wireless pen apparatus that can be used to write and to produce and store electronic signals for subsequent transfer to other equipment.
Various writing devices for inputting information to equipment such as computers have been in widespread use for many years. For example, graphical data tablets that use a stylus for writing or pointing are common computer input devices, and operate on various physical principles, for example distance ranging using acoustic energy that travels through air, through a solid surface, or through magnetostrictive wires, or electromagnetic energy that travels through a conductive grid. These devices have conventionally had a wire connected to the stylus for providing power, timing, and other necessary functions, or required a digitizer tablet underneath the writing surface.
Attempts have been made to develop a wireless electronic pen that does not have to be tethered to other equipment. Reference can be made, for example, to U.S. Pat. Nos. 5,215,397, 5,227,622, and 5,247,137. However, no wireless electronic pen for obtaining electronic signals representative of writing has become commercially viable, for a number of reasons. Some approaches would require too much power at the pen, which would quickly run down the battery in the pen that provides power. Other approaches would require a pen that is too bulky. Still other approaches do not provide sufficient resolution and/or accuracy for reliable handwriting input.
It is among the objects of the present invention to provide an electronic portable wireless pen that overcomes disadvantages of prior approaches.
A form of the present invention is directed to a method for producing signals representative of writing by a user of a wireless pen, comprising the following steps: providing a first subsystem for determining absolute position of a location on the pen with respect to a geometrical reference spaced from the pen; operating the first subsystem at time intervals to obtain absolute position indications; providing a second subsystem that is operative to determine relative position excursions of the tip of the pen; and producing signals representative of said writing from the combination of the absolute position determinations and the relative position determinations. Among the advantages of this form of the invention is that the first subsystem operates at time intervals and uses less power than continuous absolute position determination would entail. In an embodiment of this first form of the invention, the step of providing the first subsystem comprises providing a first subsystem that implements distance ranging in either or both directions between said location on the pen and a plurality of locations on the geometrical reference. In this embodiment, the first subsystem implements distance ranging using ultrasonic energy in one of the directions between said location on the pen and the plurality of locations on the geometrical reference and implements infra-red signaling in the other of the directions between said location on the pen and the plurality of locations on the geometrical reference.
A further form of the invention is directed to a wireless pen apparatus for producing signals representative of writing by a user of the pen, which includes the following: a wireless pen; a removable cap on the pen; and means, operable when the cap is removed from the pen and placed at a reference position, for communicating wave energy between at least one location on the pen and at least one location on the cap for determining the position of the at least one location on the pen with respect to the reference position of the cap, and for producing signals that depend on the determined position of said at least one location on the pen. Thus, in this form of the invention, the pen and its cap achieve a self-contained wireless pen apparatus that can efficiently capture writing of the user and store same in electronic form for subsequent transfer to external equipment such as a computer or a personal digital assistant (xe2x80x9cPDAxe2x80x9d). In an embodiment of this form of the invention, the wave energy is optical radiation, the optical radiation is transmitted from said at least one location on the pen, and the cap has first and second optical sensor arrays at said first and second locations, respectively.
A still further form of the invention is directed to a method for producing and transferring signals representative of writing by a user of a wireless pen, comprising the following steps: providing a communications subsystem on the pen; providing a wristwatch that has a communications subsystem for communicating with the communications subsystem on the pen; and communicating signals from the pen to the wristwatch that are indicative of the position of the tip of the pen.
Further features and advantages of the invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings.